Rush University Medical Center

About: Rush University Medical Center is a healthcare organization based out in Chicago, Illinois, United States. It is known for research contribution in the topics: Population & Medicine. The organization has 13915 authors who have published 29027 publications receiving 1379216 citations. The organization is also known as: Rush Presbyterian St. Luke's Medical Center.

Double Dissociation Between Memory Systems Underlying Explicit and Implicit Memory in the Human Brain

Abstract: Amnesic patients have impaired explicit memory that is evident in poor recall and recognition of words, yet can have intact implicit memory for words as measured by repetition priming, the enhanced efficiency for reprocessing those words The dissociation between explicit and implicit memory for words is a fundamental characteristic of normal cognition that could reflect two different functional architectures of the human brain two separate processing systems or two levels of operation of a single system with implicit memory less demanding of that system We present a patient who has a lesion in the right occipital lobe and who showed intact explicit and impaired implicit memory for words The deficit was specific to visual priming The double dissociation between explicit and implicit visual memory for words indicates that separate processing systems mediate these two forms of memory, and that a memory system in right occipital cortex mediates implicit visual memory for words

IFITM proteins restrict viral membrane hemifusion

Abstract: The interferon-inducible transmembrane (IFITM) protein family represents a new class of cellular restriction factors that block early stages of viral replication; the underlying mechanism is currently not known. Here we provide evidence that IFITM proteins restrict membrane fusion induced by representatives of all three classes of viral membrane fusion proteins. IFITM1 profoundly suppressed syncytia formation and cell-cell fusion induced by almost all viral fusion proteins examined; IFITM2 and IFITM3 also strongly inhibited their fusion, with efficiency somewhat dependent on cell types. Furthermore, treatment of cells with IFN also markedly inhibited viral membrane fusion and entry. By using the Jaagsiekte sheep retrovirus envelope and influenza A virus hemagglutinin as models for study, we showed that IFITM-mediated restriction on membrane fusion is not at the steps of receptor- and/or low pH-mediated triggering; instead, the creation of hemifusion was essentially blocked by IFITMs. Chlorpromazine (CPZ), a chemical known to promote the transition from hemifusion to full fusion, was unable to rescue the IFITM-mediated restriction on fusion. In contrast, oleic acid (OA), a lipid analog that generates negative spontaneous curvature and thereby promotes hemifusion, virtually overcame the restriction. To explore the possible effect of IFITM proteins on membrane molecular order and fluidity, we performed fluorescence labeling with Laurdan, in conjunction with two-photon laser scanning and fluorescence-lifetime imaging microscopy (FLIM). We observed that the generalized polarizations (GPs) and fluorescence lifetimes of cell membranes expressing IFITM proteins were greatly enhanced, indicating higher molecularly ordered and less fluidized membranes. Collectively, our data demonstrated that IFITM proteins suppress viral membrane fusion before the creation of hemifusion, and suggested that they may do so by reducing membrane fluidity and conferring a positive spontaneous curvature in the outer leaflets of cell membranes. Our study provides novel insight into the understanding of how IFITM protein family restricts viral membrane fusion and infection.

Osteoarthritic lesions: involvement of three different collagenases.

Abstract: Objective. To assess the presence of fibroblast collagenase (MMP-1), neutrophil collagenase (MMP-8), and collagenase 3 (MMP-13) in osteoarthritic (OA) cartilage, with particular emphasis on areas of macroscopic cartilage erosion. Methods. Messenger RNA (mRNA) levels were assessed by reverse transcriptase-polymerase chain reaction (RT-PCR), in situ hybridization, and Northern blot analysis. Results. MMP-1 and MMP-13 were expressed at higher levels by OA chondrocytes than by normal chondrocytes. In addition, mRNA for MMP-8 was present in OA cartilage but not normal cartilage by PCR and Northern blot analyses. Chondrocytes from areas surrounding the OA lesion expressed greater quantities of MMP-1 and MMP-13 compared with normal chondrocytes, suggesting local modulation by mechanical and inflammatory factors. Tumor necrosis factor α stimulated the expression of all 3 collagenases. Retinoic acid, an agent which induces autodigestion of cartilage in vitro, stimulated only the expression of MMP-13. Conclusion. These findings suggest a key role of MMP-13 and MMP-8, as well as MMP-1 in osteoarthritis.

Minimally invasive total hip arthroplasty development, early results, and a critical analysis

Abstract: Hip replacement with use of small incisions has been practiced selectively by a few practitioners for many years, but only in the last several years has so-called minimally invasive hip replacement been widely introduced to the majority of orthopaedic surgeons. Minimally invasive hip replacement, in fact, is not a single type of surgery but rather is a family of operations designed to allow total hip replacement to be done through smaller incisions, potentially with less soft-tissue disruption. The three main methods involve a combination of a small incision and a posterior approach to the hip, a combination of a small incision and an anterior approach to the hip, or two small incisions performed with use of the Smith-Peterson interval for acetabular placement and the approach usually used for femoral intramedullary nailing for femoral component insertion. Minimally invasive total hip arthroplasty has created much controversy among orthopaedic surgeons and a great deal of publicity in the popular press. Advocates emphasize the potential for these methods to reduce soft-tissue trauma and thereby reduce operative blood loss, postoperative pain, and hospitalization time; speed the postoperative recovery; and improve the cosmetic appearance of the surgical scar. Advocates view minimally invasive total hip arthroplasty as a logical extension of less invasive methods that have revolutionized other fields, such as arthroscopy, laparoscopic cholecystectomy, and cardiac surgery, just to name a few. Those with reservations about minimally invasive total hip replacement point out that conventional hip replacement already provides excellent pain relief, functional improvement, and durability with a low complication rate. Skeptics are concerned that minimally invasive procedures introduce new potential problems related to reduced visualization at the time of the operation, such as implant malposition, neurovascular injury, poor implant fixation, or compromised long-term results. Advocates of minimally invasive methods believe that minimally invasive hip arthroplasty holds …